Motorsailer with pilothouse in front

[YuriB]

Hi Folks,
i've got an old fiberglass minesweeper hull about 100ft long. The hull configuration itself is suitable for rebuilding her in to sailing vessel. While i'm collecting cash for project design, i decided to start modifying pilothouse. On the minesweepers it is located i front of the boat. I need your opinion wheither to leave it as it is in front, but lower 1 level down, which will look pretty good with sails either and take less efforts rather then build new pilot house in the aft.
Would like to listen all conns except visibility of sails-this can be resolved by glass windows in the roof.
http://photofile.name/photo/yuke/2874078/large/98083059.jpg
Thanks

[TeddyDiver]

What's your plans with the boat? The most essential thing to know about a boat/ship what it's used for. Just building for fun you can make pretty much anything. Sailing with paying guests from Murmansk to Bering sea is another case..

[charmc]

Hi, Yuri,

Welcome to the forums. There are many experienced designers here who can advise you on the details of your conversion, but center and even forward pilothouse motorsailers are out there. Here is one example:

"The raised pilothouse is up three steps from the main salon where a center mounted helm provides excellent visibility forward and along either side. In the aft starboard corner of the pilothouse is a very large open ships' office with built-in computers, weather fax and all necessary electronics. Also, a very special feature of LA PERLA is two additional doors from the bridge. One leads directly out on to the port side of the fore deck and makes it very easy for the captain to access the deck for docking or anchoring maneuvers. The other special staircase is a half spiral in custom teak leading up to the flybridge area"

Teddy's point is important: the pilothouse location is only one factor in designing the best layout for your intended purpose. IMHO you'll need to reduce the height quite a bit, but La Perla shows that a forward pilothouse can be integrated into a well functioning and good looking vessel. Then, of course, there's Athena. Not your average motorsailer, but has a forward bridge and looks great.

[TeddyDiver]

Those two vessels Charm represented look great and functional. Having the superstructure "evenly" fore and aft makes the profile well balanced..

[YuriB]

Thank you. But still there is no info how that big boats sail upwind. Probably only with engines.
The boat will be used for sailing anywere but with non paying guests)).
Regarding the height, height of the wheel house affects the ability to sail upwind, this is for sure, but at what proportion to the boat lenght? From the other hand if upwind blows towards the bow at small angle, there is just a small cross section of the hull and pilothouse resist to the wind, unlike for example,sailing halfwind. So my decision would be to leave the wheelhouse on the same place. Reducing the height by 10inch down will not probably improve upwind behavour much.

[yipster]

i like the idea of a fwd pilothouse
boat will need a keel and calculations
100 ft fiberglass or lapstrake?
eighter way, great hull, keep us updated

[TeddyDiver]

But still there is no info how that big boats sail upwind.
Regarding the height, height of the wheel house affects the ability to sail upwind, this is for sure, but at what proportion to the boat lenght?
So my decision would be to leave the wheelhouse on the same place. Reducing the height by 10inch down will not probably improve upwind behavour much.
More relevant issue than the resistant of the wheelhouse is the fact you would have your sails higher and the center of effort higher too. This reduces the sail carrying ability of the vessel and reduces the overall performance. A big boat has however more stability than smaller ones, but I would chop the second floor of wheelhouse anyway..
To your questio, yes, your boat could sail upwind. How well is much more complicated than just the wheelhouse properties..

[charmc]

I would chop the second floor of wheelhouse anyway. To your questio, yes, your boat could sail upwind. How well is much more complicated than just the wheelhouse properties..

I agree with Teddy on both points.

[FAST FRED]

visibility of sails-this can be resolved by glass windows in the roof.

Doesn't much matter , most cruisers set the sails "close enough" and seldome tinker or take in a sheet 2 or 3 inches as a racer might.

When the boat leans too much , or the sails flog , no need to look, just go trim them.

FF

[Finlander]

YuriB, I like your sail plan. All roller furlings would be best of course.

Cons of having pilothouse in front:
you won't see what's in front of the vessel when working on deck (unless you happen to be standing on the bow); someone will always need to be inside the pilothouse keeping watch.

Pros of having pilothouse in front:
you can earn extra cash by sweeping mines :D

Seriously, if you are doing a major refit, with all new electronics and steering system, then maybe it would be worthwhile to consider moving the pilothouse toward the back. You can add a nice covered deck-lounge for parties...

If it's too difficult, then I'm sure it would be fine where it is now (but chopped down, as you mentioned).

Either way, it'll be quite a nice ship when completed!

[YuriB]

Thank you all for the comments.
Sail plan is not yet finally considered as we have to calculate stability assuming that there will be no keel. I only plan to put cast iron ballast in the hull and thats it. A roller furlings this long may raise center of gravity due to their weight. There should be good combination found of the ballast weight, masts height, sail plan, etc.

[Tad]

Yuri,
Correct, everything must be considered at once as a complete system. The rig works with the hull and appendages, or not!

Below is a quick revision of the rig which will have more windage (drag) but be more versatile and easier to control/sail at optimum with a small crew.

22413

[YuriB]

Thanks Tad for the sail model,
3 small masts instead of 2 long ones make sense, not only due to the low point of wind pressure, but also from finacial point:conventional aluminium small yacht masts can be ordered for less price.

[Tad]

Yuri,

Steel pipe may also make some sense for masts, depending on various other factors.

[FAST FRED]

But still there is no info how that big boats sail upwind. Probably only with engines.


With a vessel that was never designed to sail , the concept of a very small engine assist while beating might make sense.

The gen set should produce a bit of thrust , if rigged right , so could be charging the battset and helping a non sailing hull to sail a bit.

FF

[YuriB]

Fast Fred, the propulson engine is in project, it is however difficult to plan anything now, because the hull has two large diameter low noise (technology stolen from USA:) ) screws in nozzles. They look nice but absolutely useless on sailing ship. We plan either remove them at all and cut in deadwood tube in the middle or just leave one (left) prop shaft and attach smaller diameter screw on it.
http://photofile.name/photo/yuke/2874078/large/98083056.jpg

[FAST FRED]

You will have to do something , no sail plan will overcome that huge drag aft.

A single CPP prop on centerline would be best , but would increase draft , and is EXPEN$IVE.

Perhaps coupling the gen set to a hyd pump would allow you to free wheel the props with small hyd motors.

The prop speed would be matched to the boat speed , just overcoming the huge drag from the props , and nozzels , but not necessarily creating added thrust. Although going to windward some extra thrust would help the course held higher .

FF

[YuriB]

We will put more ballast in front to lift stern a bit, for reducing drag.
I expected to have some drag from the prop. And will hook DC generator on the shaft-i will loose 1-2knots because of the drag but will have free electricity source on the boat. Hyd motor could be good idea but those who create good torque are not small at all. Biggest i could go with makes 1400HM, which is not enough torque for 30-35" diameter prop.(and its weight 70kg ).

[FAST FRED]

which is not enough torque for 30-35" diameter prop

Remember simply turning the prop at a speed that matches the water flow requires no power for propulsion.

You simply want to cancel the drag , make the props "invisible" as drag , and cancel the drag of the stuffing box and bearings .

Not that much power.

FF